Generative AI makes things up so I'm surprised that you seem surprised. For some situations checking the documentation is still the best option.
I know LLM’s hallucinate. I’m surprised how convincing and how stubborn it insisted it’s right. Other LLM’s would have given up and admit they don’t know.
The other day I wanted to use a function in an unfamiliar library. Gemini kept putting an argument into the call that wasn't supposed to be there even after I explicitly told it not to. This was after I trusted Gemini, got an error message and looked at the docs. The argument it was adding was required for other functions in other libraries the same subject area so I suppose that's why it did it.
Wrong library version is also a classic.
At some point it would be nice if someone could come up with a way of grounding/adding package docs and/or version as part of the context automatically
Gemini told someone I know that golang have manual memory management and was very adamant about it.